Dresden 2006 – wissenschaftliches Programm

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O: Oberflächenphysik

O 41: Electronic structure III

O 41.9: Vortrag

Donnerstag, 30. März 2006, 17:00–17:15, WIL B321

Ab initio study of non-reconstructed clean and H-passivated SiC(0001) surfaces — •Tassilo Dannecker, Alexander Mattausch, and Oleg Pankratov — Theoretische Festk"orperphysik, Staudtstr. 7, 91058 Erlangen

The SiC(0001) surface is regarded as a two-dimensional Mott-Hubbard insulator [1]. Up to now mostly the reconstructed √3×√3R30^∘-surface has been studied, whereas the 1× 1-surface was considered as unstable. However, recently the 1× 1-structure was stabilized by H-passivation. Moreover, after the hydrogen removal the surface remains metastable [2]. Early DFT-LDA calculations suggested a metallic character of both 1× 1- and √3×√3R30^∘-surfaces [3]. However, experimentally the surfaces are semiconducting. For the √3×√3R30^∘-surface it was suggested that the Hubbard correlations are responsible for its semiconducting state [1]. In this work we focus on the Si-terminated (0001) as well as the C-terminated (0001) side. We consider both clean and H-passivated surfaces. In particular, we study the nature of the surface electron states and in case of the H-passivated surface we discuss the resonant surface states, which are induced by the hydrogen-surface interaction.

[1] V.I. Anisimov et al., Phys. Rev. B, 61 (2000) 1752.

[2] T. Seyller, J. Phys.: Condens. Matter, 16 (2004) 1755.

[3] M. Sabisch, P. Kr"uger and J. Pollmann, Phys. Rev. B 55 (1997) 10561.